grab r1369300 and 1369431 from trunk:

mention migration from ap_requires() and to ap_runtime_dir_relative()

fix formatting of DEFAULT_REL_RUNTIMEDIR


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1369432 13f79535-47bb-0310-9956-ffa450edef68